Solid propelled rocket motors are designed to have many shapes and sizes. The solid propellant composition can be cast into a rocket motor case, with or without insulation, and cured in the rocket motor case. The solid propellant grain can also be formed and then inserted into a rocket motor case with or without insulation. Additionally, solid propellant rocket motors have been constructed by winding glass fibers onto the propellant grain while the glass fiber is coated with a curable resinous material that is subsequently cured.
All of the techniques for constructing rocket motors include some procedure for ensuring that the grain is integral with rocket motor case, insulation, is used, and the liner material. If voids exist between the propellant grain and the adjacent members of the rocket motor, numerous problems can develop which can attribute to failure of the rocket motor and the mission intended therefor. Therefore, the liner composition or the liner-barrier composition that is used to bond the propellant grain to either the liner or the case must meet at least two basic requirements. The liner-barrier or liner composition has to be compatible with, and bond satisfactorily to the propellant and to the insulation and other inert components of the rocket motor. The liner composition or liner-barrier composition has another problem to compete against, that is, the problem of plasticizer-catalyst migration after the propellant grain is cast. This migration problem can cause a development of a void and penetration of insulation material to produce undesirable smoke from combustion of insulation material and perhaps, complete failure of the rocket motor unless prior safeguards are taken to resist the attack of migrated plasticizer-catalyst at the interface of the propellant and liner. Therefore, it is essential that catalyst migration be discouraged or preferably eliminated by the liner-barrier composition to enable the continued use of the desirable carborane catalysts.
An object of this invention is to provide an improvement to liner-barrier composition which reduces the permeability of the liner-barrier to migrated plasticizer-catalysts.
A primary object of this invention is to provide a highly effective liner-barrier for use with carborane-containing ultrahigh burning rate propellants.